Its Greek to them: A Whole Foods yogurt conspiracy?

Or maybe it's a big, fat Greek yogurt conspiracy designed to give the health-conscious grocer Whole Foods the edge in an ultra-competitive market.

Don't worry, though. This is nothing that a couple of class-action lawsuits can't fix.

On Monday, the lawyers who made headlines for suing Subway over the length of its so-called foot-long sandwiches filed a lawsuit in Philadelphia Common Pleas Court claiming that Whole Foods is selling Greek yogurt with nearly six times the sugar listed on the label.

"I find it hard to believe they don't know what's in their yogurt," said lawyer Joseph Osefchen of the Center City and Marlton, N.J., firm DeNittis Osefchen. "It's a store brand. Whole Foods makes it, advertises it and makes the label."

The lawsuit alleges that the Texas-based supermarket chain is misleading consumers by listing its 365 Everyday Value Plain Greek Yogurt as having only 2 grams of sugar. Last month, Consumer Reports analyzed six samples of the yogurt and found that the containers had 11.4 grams of sugar, on average.

"Basically, they're saying, 'Our product has half as much sugar as our lowest competitor,' " Osefchen said. "If you're going to sell yourself as the health-food grocery store, you ought to be right."

Osefchen's firm filed the suit in Philadelphia on behalf of city residents Carmine Clemente and Samantha Kilgallen. The lawyers are seeking class-action status that would cover all Pennsylvanians who bought the yogurt. They filed a similar lawsuit in New Jersey on Friday on behalf of Whole Foods consumers there.

A Whole Foods spokeswoman said Monday that the company doesn't comment on pending litigation, but issued a statement: "We strive to only provide the highest quality products with accurate product labeling under our 365 Everyday Value line. This product was tested by a reputable third party lab using FDA-approved testing methodology to determine the labeling. We recognize that Consumer Reports is a trusted publication and are looking into why their test results differ from ours."

Osefchen said he was surprised that Whole Foods hasn't changed the labels or pulled the product after Consumer Reports published its findings in mid-July. He said he stops at the chain's Marlton store about once a week.

"Every time, I expect to see a stock boy pulling it off the shelves," Osefchen said. "For diabetics, it's a matter of life and death to monitor your sugar intake."

Greek yogurt, a thick, high-protein dairy product that has become extremely popular in recent years, was selling quickly Monday at the Whole Foods on South Street. Few shoppers seemed concerned about the allegedly misleading label.

"Still better than eating a doughnut for breakfast," said one woman, as she grabbed a different brand of Greek yogurt.

"That seems like a pretty aggressive lawsuit," said another shopper, "unless they're all diabetics."

DeNittis Osefchen gained widespread recognition in January 2013 when it sued Subway for selling foot-long sandwiches that were slightly less than 12 inches long. The world's biggest fast-food chain later said it had "redoubled our efforts to ensure consistency and correct length in every sandwich we serve."

Osefchen said the Whole Foods lawsuit is about making the company list the correct sugar content, not lining the pockets of yogurt eaters.